Prognostic impact of the number of lymph nodes examined in different stages of colorectal mucinous adenocarcinoma

Association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer: a systematic review and meta-analysis

OBJECTIVE

Clinical practice guidelines recommend retrieving at least 12 lymph nodes for correct staging in colorectal cancer. However, it is difficult to retrieve adequate lymph nodes because of various factors. We aimed to evaluate the association between the number of retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer.

DESIGN

Systematic review and meta-analysis of primary studies.

DATA SOURCES

PubMed, Embase, Cochrane and Web of Science were searched from January 2016 to June 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that evaluated the association between retrieved lymph nodes and demographic/tumour-related characteristics in colorectal cancer were included.

DATA EXTRACTION AND SYNTHESIS

OR with 95% conference intervals was extracted and pooled.

RESULTS

A total of 54 studies containing 2 05 821 patients were included in this meta-analysis. The results showed that fewer nodes were retrieved from elderly patients (OR=0.70, 95% CI (0.54 to 0.90), p=0.005), and from tumours located in the left colon than in the right colon (OR=0.43, 95% CI (0.33 to 0.56), p<0.001). More lymph nodes were obtained from females than males (OR=1.15, 95% CI (1.04 to 1.28), p=0.006), from the advanced T stage (T3+T4) than T1+T2 stage (OR=1.57, 95% CI (1.25 to 1.97), p<0.001) and from the N2 stage than N0 stage (OR=1.32, 95% CI (1.15 to 1.51), p<0.001). Body mass index, ethnicity, N1 stage, M stage, tumour differentiation and lymph-vascular invasion were not significantly associated with the lymph node yield.

CONCLUSIONS

The study results suggest that clinicians have an increased opportunity to retrieve sufficient lymph nodes for accurate pathological staging to guide treatment decisions in patients with colorectal cancer who are young, female, with tumours located in the right colon, advanced T stage and N2 stage.

Mucinous adenocarcinoma: A unique clinicopathological subtype in colorectal cancer

Mucinous adenocarcinoma (MAC) is a unique clinicopathological subtype of colorectal cancer, which is characterized by extracellular mucinous components that comprise at least 50% of the tumor tissue. The clinical characteristics, molecular features, response to chemo-/radiotherapy, and prognosis of MAC are different from that of non-MAC (NMAC). MAC is more common in the proximal colon, with larger volume, higher T-stage, a higher proportion of positive lymph nodes, poorer tumor differentiation, and a higher proportion of peritoneal implants compared to NMAC. Although biopsy is the main diagnostic method for MAC, magnetic resonance imaging is superior in accuracy, especially for rectal carcinoma. The aberrant expression of mucins, including MUC1, MUC2 and MUC5AC, is a notable feature of MAC, which may be related to tumor invasion, metastasis, inhibition of apoptosis, and chemo-/radiotherapy resistance. The genetic origin of MAC is mainly related to BRAF mutation, microsatellite instability, and the CpG island methylator phenotype pathway. In addition, the poor prognosis of rectal MAC has been confirmed by various studies, and that of colonic MAC is still controversial. In this review, we summarize the epidemiology, clinicopathological characteristics, molecular features, methods of diagnosis, and treatments of MAC in order to provide references for further fundamental and clinical research.

Tumor sidedness influences prognostic impact of lymph node metastasis in colon cancer patients undergoing curative surgery

This study aimed to evaluate prognostic impacts of the number of lymph nodes (LNs) examined and LN ratio on cancer-specific mortality after surgery in patients with right-sided colon cancer (RCC) or left-sided colon cancer (LCC) using the Surveillance, Epidemiology, and End Results database. Number of LNs examined and LN ratio were treated as categorical and/or continuous. Competing risks proportional hazards regressions adjusted by propensity score were performed. All included patients had stage I, II, or III disease, and 45.1% of them had RCC. RCC and LCC patients with high level of LNs examined had better prognosis after segmental resection or hemicolectomy. RCC and LCC patients with higher LN ratio had worse prognosis regardless of surgery. Survival benefit of having high level of LNs examined was observed in RCC patients with stage I, II, or III disease, but only in LCC patients with stage II disease. Both higher LN ratio and high level of LN were negative prognostic factors for cancer-specific mortality in stage III patients regardless of tumor sidedness. In conclusion, RCC patients in various conditions had worse or comparable prognosis compared to their LCC counterparts, which reflected the severity of LN metastasis.

Visceral obesity and short-term outcomes after laparoscopic rectal cancer resection

BACKGROUND

Complications after rectal resection are frequent. Recently, methods to assess visceral obesity (VO) have become available as an alternative to measurement of body mass index (BMI). The aim of this study was to examine the association between visceral fat volume (VFV) and the short-term outcomes after laparoscopic low anterior resection (LLAR) in patients with rectal cancer.

METHODS

We studied a consecutive series of patients undergoing LLAR at Bispebjerg University Hospital from 01.01.2013 to 01.01.2016. Preoperative VFV was calculated from abdominal CT scans using an automatic segmentation tool. The primary outcome was anastomotic leakage (AL). Secondary outcomes included conversion to open surgery, number of lymph nodes harvested, the rates of 30-day complications as well as reoperations, and 1-year survival.

RESULTS

A total of 102 patients were included. VO was defined as a VFV above the 75 percentile. Thirteen (12.7%) patients developed AL, four (15.4%) of whom were in the VO group (p = 0.900). At least one postoperative complication developed in 38 (37.3%) patients, with no significant difference between the VO and non-VO patients after univariable analysis (42.3% vs. 35.4%, p = 0.702) or multivariable adjustment (OR 1.01, 95% CI 0.38-2.65, p = 0.984). VO was significantly associated with an increased incidence of conversion to open surgery (OR 4.30, 95% CI 1.29-14.86, p = 0.018). There was a significant difference in the number of harvested lymph nodes between the two groups (mean 23.5 vs. 29.1, p = 0.045).

CONCLUSIONS

In this study on patients undergoing laparoscopic rectal resection, VO was not associated with development of AL or other complications. However, we found that visceral obesity was associated with an increased risk of conversion to open surgery.